import launch
import launch_ros
from ament_index_python.packages import get_package_share_directory


def generate_launch_description():
    #获取默认urdf路径
    urdf_package_path = get_package_share_directory('fishbot_description')
    default_urdf_path = urdf_package_path + '/urdf/first_robot.urdf'
    default_rviz_config_path = urdf_package_path + '/config/display_robot_model.rviz'
    # 声明一个urdf目录的参数，方便修改
    action_declare_arg_mode_path = launch.actions.DeclareLaunchArgument(
        name='model',default_value=str(default_urdf_path),description='urdf的绝对路径')
    #获取文件内容生成新的参数
    robot_description = launch_ros.parameter_descriptions.ParameterValue(
        launch.substitutions.Command(
            ['xacro ',launch.substitutions.LaunchConfiguration('model')]),
            value_type=str)
    #状态发布节点
    robot_state_publisher_node = launch_ros.actions.Node(
        package='robot_state_publisher',
        executable='robot_state_publisher',
        parameters=[{'robot_description':robot_description}]
    )
    #关节状态发布节点
    joint_state_publisher_node = launch_ros.actions.Node(
        package='joint_state_publisher',
        executable='joint_state_publisher'
    )
    #RViz节点
    rviz_node = launch_ros.actions.Node(
        package='rviz2',
        executable='rviz2',
        arguments=['-d',default_rviz_config_path]
    )
    

    return launch.LaunchDescription([
        action_declare_arg_mode_path,
        joint_state_publisher_node,
        robot_state_publisher_node,
        rviz_node
    ])